The role of cyclooxygenase isoforms in sporadic colorectal carcinogenesis

Ciklooksigenaze su ključni enzimi u biosintezi prostanoida. Postoje dvije izoforme: COX-1 koja je povezana s održavanjem fizioloških uvjeta u sluznici debelog crijeva; te inducibilna izoforma COX-2 koja je uglavnom povezana s patološkim procesima uključujući karcinom debelog crijeva. Cilj ovog istraživanja bio je ispitati ulogu COX izoformi u razvoju i napredovanju sporadičnoga karcinoma debeloga crijeva, mehanizme njihove regulacije te povezanost regulatornih polimorfizama gena COX-1 i COX-2 sa sklonošću obolijevanju i ekspresijom mRNA i proteina. Naši rezultati su pokazali da COX-1 ima zaštitnu, a COX-2 tumorigenu ulogu u sluznici debelog crijeva. Gubitak COX-1 učestali je događaj u karcinogenezi, dok COX-2 pokazuje veću varijaciju između uzoraka. Porast COX-2 ekspresije povezan je s lošijim preživljenjem oboljelih. Dokazali smo povezanost regulatornih polimorfizama sa sklonošću obolijevanju i ekspresijom gena COX-2. Ekspresija proteina odgovara mRNA ekspresiji te nema povezanosti s ekspresijom miR-200 što pokazuje da je ekspresija gena COX-1 i COX-2 primarno regulirana na razini transkripcije.Cyclooxygenases are the key enzymes in prostanoid biosynthesis. Two isoforms exist: COX-1, associated with maintainance of physiological conditions in colon; and inducible COX-2 that is mainly related to various pathologies including colorectal cancer. The aim of our study was to examine the role of COX isoforms in development and progression of sporadic colorectal cancer, mechanisms of their regulation and whether regulatory polymorphisms in COX genes are related to cancer susceptibility, mRNA and protein expression. Our results show that COX-1 has protective, and COX-2 tumorigenic role in colorectal mucosa. Loss of COX-1 is very frequent in carcinogenesis, while COX-2 shows greater variation between samples. Higher COX-2 expression correlates to worse patient survival. We proved the role of regulatory polymorphisms in cancer susceptibility, and COX-2 expression. Protein expression correlates with mRNA expression, and there is no associtation with miR-200, which indicates transcriptional regulation as the key regulatory mechanism of COX expression

Cyclooxygenase Isoforms in Tumorigenesis

Cyclooxygenases (COXs) are the key enzymes in prostanoid biosynthetic pathway. Prostanoids act as local hormones and they are involved in numerous normal physiological proceses but also in the development of various diseases. COXs are present in three isoforms: COX1, COX2 and COX3. COX1 is usually involved in maintaining the physiological conditions of the healthy tissues while COX2 is mainly related with various malignancies. COX3 is a functional splice variant of COX1 and its role is still controversial. COX1 has a housekeeping role while COX2 has been implicated in tumorigenesis.COX2 overexpression has been detected in premalignant and malignant lesions in different tissues. Numerous experiments confirmed its role in all stages of tumor development. It was reported that COX2 participates in promotion of angiogenesis and inhibition of apoptosis and immunosurveillance. The exact mechanisms of its activity in these processes are not fully clarified. Expression of COX2 has been proposed to be an early event in colorectal tumorigenesis. Different drugs were developed to target COX and they were effective in preventing cancer but they also exhibited adverse effects. There is extensive research conducted in order to develop the drug that wouldn’t cause severe toxicities and to define the polymorphisms that affect the patients response to a certain drug but also to define the cancer risk polymorphisms

The role of cyclooxygenase isoforms in sporadic colorectal carcinogenesis

Ciklooksigenaze su ključni enzimi u biosintezi prostanoida. Postoje dvije izoforme: COX-1 koja je povezana s održavanjem fizioloških uvjeta u sluznici debelog crijeva; te inducibilna izoforma COX-2 koja je uglavnom povezana s patološkim procesima uključujući karcinom debelog crijeva. Cilj ovog istraživanja bio je ispitati ulogu COX izoformi u razvoju i napredovanju sporadičnoga karcinoma debeloga crijeva, mehanizme njihove regulacije te povezanost regulatornih polimorfizama gena COX-1 i COX-2 sa sklonošću obolijevanju i ekspresijom mRNA i proteina. Naši rezultati su pokazali da COX-1 ima zaštitnu, a COX-2 tumorigenu ulogu u sluznici debelog crijeva. Gubitak COX-1 učestali je događaj u karcinogenezi, dok COX-2 pokazuje veću varijaciju između uzoraka. Porast COX-2 ekspresije povezan je s lošijim preživljenjem oboljelih. Dokazali smo povezanost regulatornih polimorfizama sa sklonošću obolijevanju i ekspresijom gena COX-2. Ekspresija proteina odgovara mRNA ekspresiji te nema povezanosti s ekspresijom miR-200 što pokazuje da je ekspresija gena COX-1 i COX-2 primarno regulirana na razini transkripcije.Cyclooxygenases are the key enzymes in prostanoid biosynthesis. Two isoforms exist: COX-1, associated with maintainance of physiological conditions in colon; and inducible COX-2 that is mainly related to various pathologies including colorectal cancer. The aim of our study was to examine the role of COX isoforms in development and progression of sporadic colorectal cancer, mechanisms of their regulation and whether regulatory polymorphisms in COX genes are related to cancer susceptibility, mRNA and protein expression. Our results show that COX-1 has protective, and COX-2 tumorigenic role in colorectal mucosa. Loss of COX-1 is very frequent in carcinogenesis, while COX-2 shows greater variation between samples. Higher COX-2 expression correlates to worse patient survival. We proved the role of regulatory polymorphisms in cancer susceptibility, and COX-2 expression. Protein expression correlates with mRNA expression, and there is no associtation with miR-200, which indicates transcriptional regulation as the key regulatory mechanism of COX expression

Imunoenzimni test i lančana reakcija polimerazom uz prethodnu reverznu transkripciju za dokazivanje perzistentne zaraze virusom virusnog proljeva goveda u skupnom uzorku krvnog seruma - kratko priopćenje.

The applicability and reliability were investigated of antigen enzyme linked immunosorbent assay (Ag ELISA) and reverse transcription polymerase chain reaction (RT-PCR) for the diagnosis of bovine viral diarrhoea (BVD) in pooled serum samples of persistently infected cattle. In this study 968 serum samples were tested and persistent infection was confirmed by Ag ELISA in six animals by sampling twice at a four week interval. Positive samples were tested undiluted and diluted by Ag ELISA and RT-PCR. Sera were diluted (fivefold) and tested once again by both methods. All undiluted samples were tested positive by Ag ELISA, while the end point dilution was 1:5. When RT-PCR was used, samples were shown to be positive to 1:125, and in one sample in a dilution of 1:625. We can conclude that Ag ELISA can be useful in the diagnosis of BVD in a maximum five pooled serum samples from persistently infected animals. RT-PCR shows greater sensitivity and thus is more appropriate for screening purposes when pooling of samples is recommended.Istražena je primjenjivost i pouzdanost Ag ELISA-e i lančane reakcije polimerazom uz prethodnu reverznu transkripciju (RT-PCR) u dijagnostici virusnoga proljeva u skupnom uzorku krvnog seruma perzistentno zaraženih goveda. Perzistentna zaraza dokazana je dvokratnim uzorkovanjem s razmakom od četiri tjedna. Ukupno je Ag ELISA-om bili pretraženo 968 uzoraka seruma goveda, a perzistentna je zaraza utvrđena u šest goveda. Uzorci seruma svih šest goveda bili su peterostruko razrijeđeni. Nerazrijeđeni i razrijeđeni uzorci bili su pretraženi usporedno Ag ELISA-om i RT-PCR om. Svi nerazrijeđeni uzorci dali su pozitivan rezultat s obje metode. Razrijeđeni uzorci pretraživani Ag ELISA-om pokazali su pozitivan rezultat do razrijeđenja 1:5. Svi razrijeđeni uzorci pretraživani RT PCR-om bili su pozitivni do razrjeđenja 1:125, a jedan uzorak do razrjeđenja 1:625. Zaključno se može reći da se Ag ELISA može rabiti u dijagnostici virusnoga proljeva goveda u skupnim uzorcima do najviše pet goveda. RT-PCR pokazao je veću osjetljivost i specifičnost u pretraživanju skupnih uzoraka krvnog seruma goveda

Allele frequencies of variants in Ultra Conserved Elements identify selective pressure on transcription factor binding

Ultra-conserved genes or elements (UCGs/UCEs) in the human genome are extreme examples of conservation. We characterized natural variations in 2884 UCEs and UCGs in two distinct populations ; Singaporean Chinese (n=280) and Italian (n=501) by using a pooled sample, targeted capture, sequencing approach. We identify, with high confidence, in these regions the abundance of rare SNVs (MAF<0.5%) of which 75% is not present in dbSNP137. UCEs association studies for complex human traits can use this information to model expected background variation and thus necessary power for association studies. By combining our data with 1000 Genome Project data, we show in three independent datasets that prevalent UCE variants (MAF>5%) are more often found in relatively less-conserved nucleotides within UCEs, compared to rare variants. Moreover, prevalent variants are less likely to overlap transcription factor binding site. Using SNPfold we found no significant influence of RNA secondary structure on UCE conservation. All together, these results suggest UCEs are not under selective pressure as a stretch of DNA but are under differential evolutionary pressure on the single nucleotide level

Cyclooxygenase Isoforms in Tumorigenesis

Cyclooxygenases (COXs) are the key enzymes in prostanoid biosynthetic pathway. Prostanoids act as local hormones and they are involved in numerous normal physiological proceses but also in the development of various diseases. COXs are present in three isoforms: COX1, COX2 and COX3. COX1 is usually involved in maintaining the physiological conditions of the healthy tissues while COX2 is mainly related with various malignancies. COX3 is a functional splice variant of COX1 and its role is still controversial. COX1 has a housekeeping role while COX2 has been implicated in tumorigenesis.COX2 overexpression has been detected in premalignant and malignant lesions in different tissues. Numerous experiments confirmed its role in all stages of tumor development. It was reported that COX2 participates in promotion of angiogenesis and inhibition of apoptosis and immunosurveillance. The exact mechanisms of its activity in these processes are not fully clarified. Expression of COX2 has been proposed to be an early event in colorectal tumorigenesis. Different drugs were developed to target COX and they were effective in preventing cancer but they also exhibited adverse effects. There is extensive research conducted in order to develop the drug that wouldn’t cause severe toxicities and to define the polymorphisms that affect the patients response to a certain drug but also to define the cancer risk polymorphisms

P2RY12 Gene Polymorphisms and Effect of Clopidogrel on Platelet Aggregation

Objective of this study was to assess platelet response to clopidogrel and its association with certain single nucleotide polymorphisms (SNPs) of the P2RY12 gene. Several studies have shown that patients with poor in vitro response to clopidogrel have worse outcomes after coronary interventions. Pharmacological response to clopidogrel is mediated by the P2Y12 platelet receptor, therefore, SNPs of the P2RY12 gene may account for some of the observed variability in the cardiovascular risk. Fifty patients with stable coronary heart disease, undergoing percutaneous coronary intervention were included in this study. Response to clopidogrel was analysed using light transmitted aggregometry before, and 5 days after the initation of therapy. SNPs analysed: c.–15+742C>T, c.–180+2739T>C and c.18C>T. A higher proportion of non-responders to clopidogrel were noted in carriers of 18C>T[T/T] (p=0.05), and lower prevalence in carriers of 742C>T[T/T] (p=0.05). Participants with 742C>T[T/T] had significantly higher change in aggregation compared to other 742C>T variants ([C/C]=20.5±21.9%; [C/T]=20.0±31.2%; [T/T]=48.6±21.3%; p=0.03). Those carrying 18C>T[T/T] had smaller change in aggregation (7.6±15.0%) compared to other variants, but the difference was not statistically significant (p=0.15). Analysis of variance showed 18C>T[T/T] was a statistically significant predictor of poor response to antiaggregation therapy, independent from other clinical and demographic variables. There was no relation between poor response to clopidogrel and any other genetic variant. Our results suggest that 18C>T SNP of the P2RY12 gene may be an independent predictor of pharmacological response to clopidogrel. Larger prospective studies are needed to confirm this link and assess its possible clinical consequences